Excavator bucket assembly



Sept. 4, 1962 c. A. wlLMs ET AL 3,052,050

ExcAvAToR BUCKET ASSEMBLY Filed Oct. 19, 1960 4 Sheets-Sheet l Sept. 4,1962 c. A. WILMs ET AL 3,052,050

ExCAvAToR BUCKET ASSEMBLY Filed oct. 19, 1960 v 4 sheets-sheet 2INVENToRs.

Sept. 4, 1962 c. A. WILMs ETAL EXCAVATOR BUCKET ASSEMBLY 4 Sheets-Sheet3 Filed 0G12.l 19, 1960 l l l I l Sept. 4, 1962 c. A. wlLMs ET AL3,052,050

EXCAVATOR BUCKET ASSEMBLY l Filed 00T.. 19, 1960 4 Sheets-Sheet 4INVENToRs. L4/Pz A. W/Ms United States Patent O 3,952,650 EXCAVATORBUCKET ASSEMBLY Carl A. Wilms, La Habra, and Fouad K. Mittry, Jr., LosAngeles, Calif., assignors to Mechanical Excavators, Inc., Los Angeles,Calif., a corporation of California Filed Oct. 19, 1960, Ser. No. 63,5213 Claims. (Cl. 37-l9il) This application relates generally to excavatingmachines, and particularly to a wheel excavator having a very largecapacity for its size.

Shovels, Adrag lines and wheel excavators are all widely used today formoving large quantities of earth, such as overburden in open pit coalmines. though the wheel excavator is one of the most efficient of thesemachines, it is considerably more complicated and therefore higher ininitial cost than either a drag line or shovel. Consequently, it isgenerally built in large sizes whereby it may be more economically ownedand operated.

-Because of the size and weight of present wheel excavaltors, it hasheretofore been necessary to mount the excavator ladder or boom forreciprocation on the tractor. It has been found simpler and lessexpensive to crowd only the wheel forward rather than the wheel and thetractor.

Present wheel excavators, due to their size, generally utilize aplurality of motors and generators for powering the wheel 'and the othermoving parts including the mast, swing `drive and conveyors. Inaddition, it has not heretofore been thought practical to power thewheel by other than electrical motors due to the varying length of thewheel boom or ladder during operation.

Yet another disadvantage of -many present wheel excavators of all sizesis the fact that `overloading of the excavator often causes breakdownswhich require extensive downtime. The structurally weakest point in thedrive system, for example, is not always readily accessible. When afailure occurs at this point, considerable time is required to tear awayand reassemble the surrounding structure.'

Accordingly, a primary object of this invention is to provide a wheelexcavator having an unusually large wheel for the size of the machinewhereby a large output for the size of the machine is possible, goodmobility at the job and from job-to-job is attained, operating andmaintenance costs are low, the machine is relatively light in weight sothat ground pressure is seldom a problem, and the machine is relativelyeconomical to own and operate.

Yet another object is to provide a new and unique method of excavatingwith a wheel excavator in which the entire excavator including thetractor, and not just the shovel ladder and wheel, is crowded forward ascontrasted to conventional methods of wheel excavating in which only thewheel advances.

Yet another object is to provide a wheel excavator having a ladder whichis pivotally mounted and swings hoiizontally with the tractor in afashion similar to that of the conventional shovel or dragline.

Yet another object is to provide a wheel excavator having a capacity upto seven times greater than that of conventional shovel excavators ofsimilar size.

Yetanother object is to provide a wheel excavator in which the specialmotors and generators usually required for powering the tractor andother moving parts of the excavator are eliminated, and the tractorpower is utilized to drive the excavator wheel.

Yet `another object is to provide a wheel excavator in which the wheelis mechanically -driven as contrasted to the conventional electricallypowered excavator wheel.

Yet `another object is to provide a wheel excavator in which thedirection of rotation of the wheel can be quickly reversed by merelypulling four bolts per bucket,

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shifting a drive sprocket, and making one other simple adjustment.

Yet a further important object is to provide an excavator wheelattachment which can be readily built into a new machine designedspecifically as a wheel excavator or just as readily attached to aconventional shovel or dragline.

Another important object is to provide a mechanical drive system for ianexcavator wheel in which a plurality of shear pins are used to transferpower from the source of power to the wheel, the shear pins beingdesigned as the weakest point in the power linkage system and beingexposed so that should the power linkage system break down at this pointit can be quickly repaired.

Other objects will .become apparent upon a reading of the followingdescription of the invention.

The invention is illustrated more or less diagrammatically in theaccompanying drawings, wherein:

FIGURE l is an elevational view (with parts omitted for -cla-rity andothers indicated only diagrammatically) of .a conventional shovel whichhas been modified by the `addition of Ian excavator wheel attachment ofthe present invention, and a steerable self-propelled mobile bin intowhich `the Wheel excavator discharges;

FIGURE `2 is a plan view of a portion of the wheel excavator of FIGURE 1with parts broken away for clarity;

FIGURE 3 is a plan view to an enlarged scale of a portion of theexcavator wheel and a portion of the associated wheel drive system;

FIGURE 4 is a side view, with parts omitted for clarity, of Ithedischarge side of the wheel showing the relative position of thetransfer conveyor with respect to the wheel; and

FIGURE 5 is a front view of the excavator wheel llustrating the relative.position of the transfer `and ladder belt conveyors.

Like reference numerals will be used to refer to like parts throughoutthe Efollowing description of the invention.

General Arrangement The wheel excavator, indicated generally at `10 inFIGURE l, is shown discharging into a steerable selfpropelled mobile bin11 which in turn discharges onto a removal conveyor l12. Although thewheel excavator *has been illustrated in conjunction with la mobile bin,it will be understood that the invention is not so limited linapplication and the bin is shown merely for purposes of description.

The wheel excavator, in this instance, is illustrated as a modifiedshovel. It consists essentially of a crawler truck unit 15 having a pairof conventional steel treads 16 resting on the ground 17. A tractor 18is mounted on any suitable turntable structure 19 on the crawler truck15.

An excavator wheel Ztl rotates about a wheel shaft 21 carried at the endof wheel excavator ladder 22. The ladder in turn is pivoted to thetractor as at 23. The ladder and excavator wheel are supported from thetractor by suspension cables 25 which are secured to the outer end of amast 26. Vertical movement of the mast 26 about pivot point 23 iseffected =by a hoist cable 2S having one end secured to the tractor asat Z9 and the other end to a reversible winch which will be describedhereinafter.

Material dug from the ground by excavator wheel 20 is discharged atsubstantially right angles to the plane in which the wheel rotates ontoa short transfer conveyor 30 which in turn discharges onto a removalladder belt conveyor 31 positioned substantially at right angles to thetransfer conveyor and parallel with the wheel ladder.

Material discharged onto conveyor 31 is carried rearwardly to a deector32. Suitable mechanism for driving the excavator wheel and conveyor 31are provided which will be described in detail hereinafter. It will beunderstood that the excavator wheel ladder and the conveyor 31 move inparallel vertical planeswith respect to one another and rotate inparallelism horizontally about the center of rotation 33.

l Material from deflector 32 drops downwardly into an apron 34 locatedat the tail end of tail conveyor 35. Conveyor 35 extends rearwardly asuitable distance and discharges into the self-propelled mobile bin 11.

Wheel Ladder The ladder consists essentially of a pair of sideframes50,' 51 ofsubstantially identical construction. The sideframes aremaintained a xed distance apart by rear plates 52 and a series of crossbraces 53. Only three cross braces are illustrated for purposes ofclarity. The forwardmost cross brace 53 is located at approximately themid portion of the ladder. The forward halves of the sideframes 'carryno cross members so as to provide no obstruction to the passage of theexcavator wheel therebetween. A pair of pivot plates 54 are welded tothe rear end of the ladder to receive pivot shaft 23 about which theladder and excavator wheel pivots vertically. A pair of yokes 55, seenbest in FIGURE 3, are welded to the -forward end of the ladder toreceive wheel shaft 21 about which the excavator wheel rotates. Aplatform 57 extends outwardly from the left side of the ladder tosupport the chain drive housing which will be described in detailhereinafter.

Excavator Wheel The excavator wheel includes a plurality of buckets 60,in this instance six, bolted to a wheel frame 61. The wheel frame iscomposed essentially of a pair of overlapping radially spaced plates 62,63I having apertures 641 aligned with the bases of the buckets. It willbe understood that the buckets are formed with an open base so thatexcavated material lwill fall from the buckets through the alignedapertures and onto the slope sheet to be described hereinafter. Anysuitable means may be utilized to secure the buckets to the rotatingwheel frame. In this instance, fourheavy bolts 65 have been utilized tosecure each bucket to outer plate 63. Suitable spacers 66 maintain theinner and outer plate 62, 63 of the rotating wheel frame a ixed distanceapart. In order to reverse the position of the buckets, the four boltsare pulled, the bucket is turned 180 degrees, and the bolts retightened.

The 'wheel frame is open on its inner or right side but is closed on itsouter or left side by an annular plate structure 67 which terminates inan inwardly extending cone 68. A 'plurality of triangular braces 69extending about the cone are welded along their hypotenuse to the coneand along their inner legs to a plate 70 which in turn is welded toapair of collars 71, 72. The collars and plate 70 form in effect ya hubfor the wheel shaft 21. A pair of roughly Z-shaped bushings 73, 74receive the hub. The bushings in turn receive a pair of roller bearings75,76 which surround the shaft 21. Suitable collars 77, 78 on the shaftrand end plates 79, 80 keep the roller bearings in place.

The short legs of braces 69 are welded to another annular plate 82 towhich a bull gear 83` is welded. Bull gear 83 is driven by asuitablepinion 84 from a power source to be later described.

Excavator Wheel Drive Power to drive the excavator wheel is supplied bya, diesel engine which is geared to the hoist drum drivey through theregular shovel drive machinery. The diesel generator set indicated at 89is an additional power source providing electricl power for the conveyordrives and any 'auxiliary drives needed. Although the diesel generatorset S9 is shown located to the rear of cab, it will beaunderstood thatwithin the scope of the. invention it may be located in `any convenientplace. In the specific emr bodiment shown, this location of the dieselgenerator set acts as a counterweight for the wheel.

Power is transferred from the power source to a hoist drum drivesprocket, indicated generally at 90, by any suitable means. lt will beunderstood that a chain or a shaft drive with direction changing gearsmay be utilized. Since the exact arrangement of the power drive from the`diesel generator to the hoist drive drum is not essential to anunderstanding of the invention, it is not further illustrated.

Power is transferred from hoist drum drive 90 to a reversing gear boxsprocket 91 by a pair of chains, terminating with chain 92. Chain 92 mayoptionally pass over a takeup or clearance sprocket 93 which is carriedby the ladder.

Reversing sprocket 91 is fixed to a first shaft 94 received in bearings95, 96, which are indicated diagrammatically only for purposes ofillustration. The bearings in turn are supported by any suitable meansin a gear case 97 which is welded to the ladder. A first gear 93 iskeyed to shaft 94 and meshes with another identical gear 99 carried on asecond shaft 16u. Shaft 100 is similarly supported in bearings 101, 162.IIt will be understood that the di- Iameters of shafts 94 and 106` aresubstantially identical so that reversing sprocket 91 may be received oneither shaft depending upon the desired direction of rotation of thewheel. Suitable bearing caps, including cap 103, close the gear case tomake it oil tight.

The output end of shaft 100 is received in the input side 1M of a shaftcoupling. The output side 105 of the coupling is connected to a wheelchain drive assembly input shaft 106.

The wheel chain drive assembly consists essentially of a wheel chaindrive housing 107 which contains an input sprocket 10S connected bychain 109 to an output sprocket 110. Housing 1017 is divided into anupper and a lower half so that it may be readily removed for inspectionand maintenance. Power is transferred from sprocket to drive pinionshaft '111 by the arrangement to be described hereinafter.

Input shaft 106 is rotatably supported by bearings 112, 1113 in any`suitable manner at the rear of the chain drive assembly housing 107.Chain 109 extends forward to output sprocket 110 and then back overtakeup sprocket 114 to the input sprocket 163. Takeup sprocket 114 iscarried at the outer end of a takeup arm 115 which in turn is pivotablearound a suitable takeup base 116. Consequently, takeup arm 11S may besecured to either the bottom or top of the chain drive assembly housingdepending upon the direction of wheel rotation. IIn order to alter thevertical position of takeup sprocket 114, a takeup assembly indicatedgenerally at 117 is provided.

The takeup assembly may be of any suitable construction. In oneembodiment for example a takeup screw is mounted for verticalreciprocable movement. The vertical screw carries a crosshead at itsupper end from which a pair of depending links extend downwardly to theshaft carrying takeup sprocket 114. When the position of base 116 isvaried, it is a simple matter to adjust the vertical position of thetakeup sprocket by simply screwing the takeup screw up or down,depending upon the desired position.

Output sprocket 110 is keyed or otherwise suitably secured to drivepinion shaft `11:1 by the following arrangement.

Sprocket y110 is welded to a sleeve 120 which is rotatably received overthe drive pinion shaft. The outer end of the sleeve is received in andsecured to the inner half 121 of a shear pin coupling. IInner couplinghalf 121 is then secured to a corresponding mating outer half 122 by aplurality of shear pins 123. The shear pins are spaced circumferentiallyabout the mating, overlying ilanges of the coupling halves. Outercoupling half l122 is then secured to the drive pinion shaft 1-11 sothat power must be transmitted through the shear pins. By a suitabledesign of the shear pins, this particular part of the power drivelinkage system can be made the weakest point and consequently should theexcavator wheel be overloaded, breakage will occur at this point. When abreakage occurs, the pins will shear but no further damage to themachine can result because the inner coupling half 121 and the powertransmission system back to the diesel generator will continue to rotateunder no load while the balance of the system is stalled. Repair istherefore extremely easy because the shear pin flanges are located in anexposed position.

Drive pinion shaft 111 is connected by suitable bearings and seals todrive pinion 84 which in turn meshes with bull gear 83 as described.Plate 124 overlies the conical opening to prevent excavated materialfrom falling into the gearing. The cover plate 124 is bolted orotherwise suitably secured to the internal surface of yoke arm 50 andprovided with a circular seal 4125 adjacent the external periphery ofthe bull -gear 83. The bull gear then rotates relative to the coverplate 124.

A pair of extensions 130, 131 project outwardly from the forwardmost endof the wheel chain drive assembly housing platform 57. Each Vextensionis formed by a pair of yoke members 132, 133 which, when assembled, forma two point support for the left end of wheel shaft 21. A collar 134 atthe outermost end of the shaft forms a housing for suitable bearings.

Transfer conveyor Material which has been removed by the wheel excavatoris conveyed rearwardly to a tail conveyor 35 by a ladder conveyor 31.Conveyor 31 is supported at its forward end by the wheel shaft 21, asillustrated diagrammatically in FIGURES 3 and 5, and at its rear ordischarge end by any suitable framework on the tractor 18. It will beunderstood that the discharge end of conveyor 31 is pivotally mounted tothe framework on the tractor and swings with it and it is likewisepivotally, rotatably mounted on the wheel shaft 21 so that as theexcavator wheel is swung upwardly and downwardly from the position ofFIGURE 1 the position of the conveyor is correspondingly altered. Ineffect, the movement of conveyor 31 and the wheel ladder is much likethe opening and closing of the blades of a pair of scissors about wheelshaft 21 as a pivot.

Excavated material is transferred from the excavator wheel to conveyor31 by structure which will now be described in detail.

Cross Conveying Assembly A plug and slope sheet assembly is indicatedgenerally at 140. The assembly consists essentially of -a plug or slopesheet y141 which is secured to and continuous with a plug structureindicated generally at 142. The ends of the plug are indicated at 143and 144 respectively and, as can be seen best in FIGURE 4, the plugextends around about two-thirds of the circumference of the wheel.Triangular side plates 145, 146 provide what is in effect a continuouschute for discharging material dropped downwardly through the openingsin the wheel plates 62, 631. As can best be seen from FIGURE 5, the plugand slope sheet are set into the body of the wheel and Overline the cone68.

The plug and `slope Vsheet are supported within the excavator wheel by asupport structure illustrated at 148 in FIGURE 4. In this instance, theplug support consists of a plurality of generally horizontal wide flangebeams 149, 150 from which a pair of Islightly downwardly inclined beams151, 152 extend. Beams 151, 152 in turn are welded to a ladder conveyortruss 153, shown best in FIGURE 1. Plug 142 is .actually secured to thewide ange beams by rearwardly and upwardly inclined plug supports. Theplug supports comprise tubular members 154, 155, 156 which are welded attheir lower ends to the wide llange beams and at their upper ends to theplug 142.

In order to more expeditiously transfer excavated material from theslope sheet to conveyor 311, a short transfer conveyor or belt feeder30, seen best in FIGURE 5, is provided. Belt feeder 30 consists of ahead or drive pulley '161 and a tail pulley 162 about which a flexibleconveyor belt 163 is trained. The drive and tail pulleys are supportedin a belt feeder frame which consists essentially of a pair of wideflange beams 164 -to which are welded end plates 165. The pulleys inturn are journaled in the end plates. A platform 166 extends rearwardly,or to the left as viewed in FIGURE 4, from the conveyor supportstructure. An electric motor 167 is supported on the platform andfurnishes power to drive pulley 161 by means of a chain and sprocketarrangement 168 best illustrated in FIGURES 4 and 5. An impact idler 169is located roughly midway between the drive and tail pulleys. Experiencehas indicated that belt wear can be considerably reduced by placing aroller in this location.

Laidder Belt Conveyor Conveyor 31 consists essentially of a truss orframework 153 lwhich supports a llexible belt conveyor indicatedgenerally at 170 (FIGURE 5). Although any suitable conveyor may beutilized, in the illustrated embodiment there is shown la flexibleconveyor which consists essentially of ya llexible belt 171 supported bya plurality of troughing idler assemblies 172. The idler assemblies aregenerally regularly spaced along the truss. It will be understood thatit may be convenient to space the troughing idler assemblies closertogether at the tail end of the conveyor, that is, the left end asviewed in FIG- URES 1 and 2, in order -to provide [more impactresistance to material discharged from the belt feeder 30. Belt 171 istrained around a tail pulley 173 which is supported by any suitablestructure, such as the pillow blocks -174 bolted to the conveyor truss.The return reach of the conveyor belt passes directly beneath theconveying reach. It may, for example, be convenient to train the returnreach over return roller assemblies which are mounted within the truss.

Any suitable means may be utilized to mount the ltransfer conveyor trussto the wheel shaft 21. In one practical embodiment, the head end of thetruss was formed by a pair of vertical plates, each plate being formedwith an elongated sl-ot which received the wheel shaft 21. AS theincluded angle between the wheel ladder and truss vary, the wheel shaftmerely slides along the elongated `slot lin the end plates.

Power to drive conveyor belt `171 is furnished by a motor 176, shownbest in FIGURE 1, mounted on a framework 177 which -is bolted at itslower ends to the conveyor truss 153. Power from the output side `ofmotor 176 is transferred by :a V-belt 178 to a speed reducer 179.Another belt 180 transfers power to the head or drive pulley 181 aboutwhich the belt is trained.

Hoist M echansm The excavator wheel ladder and conveyor 31 are elevatedin a vertical plane by lthe hoisting mechanism next to be described.

A mast 26 is pivoted at its lower end about the same axis as the ladder22 and terminates at its upper end in a pair of 'sheaves or pulleys 186.The suspension cables 25 are secured at both their lower and upper endsto triangular gu-sset plates 188, 189 which in turn are pivotallymounted to the ladder and the upper end of the mast respectively.

A gantry `assembly is indicated generally 'at 190. The assembly includesa linkage comprising individual arms 191, 192, i193, each of which ispivoted to the tractor at its lower end. A link 194 pivotally connectslink 191 to.

links 192 and 193.- The hoist cable 28 is anchored to rearmost link 193as `at 29, and extends back and forth between sheaves (not shown)located adjacent the upper ends of mast 26 and link 191. The free end ofhoist cable 28 is received on a suitable winch carried yin the tractorwhich is actuated by any suitable drive mechanism, not shown. Since such`a gantry assembly is conventional inthis art, it is not thoughtnecessary to further illustrate it in detail.

Tail Conveyor Tail conveyor 35 is pivotally mounted to the tractor by apivot frame assembly indicated generally at 196. In this instance, aturntable 197 has been shown but it will be realized that within thescope of the invention any suitable structure for providing rotation ofthe discharge conveyor |about a center of rotation on the tractor may beutilized. A tail conveyor 35 consists essentially of a conveyor belt 201supported by a plurality of troughing idler assemblies 202 which in turnare supported from the conveyor -truss 203. Any suitable source of powersuch as an electric motor 204 carried by a framework at the outer end ofthe conveyor truss provides driving power to head or `drivel pulley 205through drive belt 206.

A gantry frame for raising and lowering the discharge conveyor isindicated generally at 208. The frame includes conveyor mast 209 whichis pivotally mounted at its lower end to the tail conveyor framework 203and extends upwardly to a point above approximately the mid portion ofthe conveyor. Suspension cables 210, 211 extend from the upper end ofthe mast to the mid portion and forwardmost end of the frameworkrespectively. A hoist cable 212 is anchored at one end to any suitablepoint and then is wrapped back and forth over sheaves carried by thegantry frame and mast to a winch 213. A motor, unnumbered, supplieswinding power to the winch to thereby raise and lower the dischargeconveyor. The winch and motor are supported on a framework welded to thetail conveyor mast.

The use and operation of the invention is as follows:

To excavate material, the excavator wheel and the tract-or are crowdedforward simultaneously. By a suitable control mechanism, not shown, theexcavator wheel ladder transfer conveyor and cab may be swung about thecenter of rotation33. As the wheel rotates, the individual buckets biteinto the ground and carry the excavated material upwardly until thebuckets reach a point a few degrees to the left of the vertical asviewed in FIGURE l. The material in the buckets then drops downwardlythrough the aligned openings in the base of the buckets and theexcavator wheel and onto the plug or slope sheet 141, shown best inFIGURE 5. From there the material drops by gravity onto the belt feeder30 which carries it to conveyor 31. Conveyor 31 in turn conveys thematerial up to the tail end of tail conveyor 35 and conveyor 35 thendeposits the material into any suitable surge hopper such as thesteerable self-propelled mobile bin indicated at 11.

During operation, the excavator wheel and conveyor 31 will make varyingangles with the tail conveyor 35 but it will be understood that thearrangement of parts is such that deector 32 will always discharge intoapron 34. In a machine designed as a wheel excavator from the ground up,it will be understood that the conveyor pivot and center of rotation maycoincide so that the conveyor 31 may be incorporated into the ladder 22.

In one commercial installation a thirty cubic yard bin has been used.The bin in turn discharges into a conveyor 12 which carries the materialto a remote processing station. Since conveyors 35 and 31 are pivotallymounted on the excavator, it is possible to move the entire excavator aconsiderable distance around the mobile bin. In other words, theposition shown in FIGURES 1 and 2 in which the conveyors are aligned, isnot the only position in which the excavator can' be operated.

Onesoffthe most unique features of the invention is the provision of amechanical drive system for the excavator wheel as contrasted to theconventional electric motor system. In this instance, the diesel enginewhich normally supplies the power to move the tractor forward has beenarranged to also provide driving power for the excavator wheel. Thepower is transferred from the diesel to the sprocket at the base of theladder and from there to the reversing gear assembly 97. Power transfershafts and 106 then transfer the power laterally to input sprocket 108of the chain drive housing. From sprocket 108 the power is transmittedto output sprocket 110 and then to pinion drive shaft 111. Pinion 184 atthe end of drive shaft 111 meshes with bull gear 83 secured to theexcavator wheel.

To 4reverse the direction of rotation from the direction indicated bythe arrows in FIGURE l, sprocket 91 is removed from shaft 94 and placedon shaft 100. Takeup sprocket 114 is then adjusted by moving pillowblock `116 from the position shown to the top of the chain drivehousing. The position of buckets 60 is easily reversed by merely pullingthe four bolts 65 by which each bucket is secured to the rotating wheel.

Another unique feature of the invention is the fact that an overloadwill cause a failure at a location which is easily accessible for repairand maintenance. Thus, shear pins 123 which transfer power from sprocket120 to drive pinion shaft 111 through the mating halves 121 and 122 ofthe shear pin `coupling are so designed as to be the Weakest link in thepower system from the source on the cab to the buckets. If the machineis crowded forward too far or extremely compact material is encountered,the pins will shear and no further damage will occur because power inputto drive pinion shaft 111 will be terminated. It is then a simple matterto remove the sheared ends of the pins, install a new set of pins, andresume operations.

Although a preferred embodiment of the invention has been illustratedand described, it will be understood that the scope of Ithe inventionshould not be so limited.

For example, the invention has been illustrated in a structure in whichthe excavator wheel and its associated support structure and conveyorshave been designed as a separate unit to be connected to a conventionalshovel. The principles of the mechanical power transmission from thetractor to the whel and the shear pin system, among others, may be justas readily incorporated into machines built from the ground up as awheel excavator.

In addition, the excavator can be made more mobile by substituting atwo-way spout at the end of the tail conveyor for the steerable mobilebin shown in the drawings. The tail conveyor may then discharge directlyinto trucks. As a consequence, there is never any need to slow down orshut down operation of the excavator, as is sometimes necessary when thelimit of the removal conveyor is reached.

Accordingly, the scope of the invention should only be limited by thescope of the following appended claims.

We claim:

1l. In la wheel excavator, a crawler truck, a tractor mounted forswinging movement in a horizontal plane about the truck as a base, anexcavator wheel, an excavator wheel ladder, said wheel being rotatablymounted on the ladder at its outboard end, said ladder being connectedto the tractor for swinging movement therewith in a horizontal plane andpivotally connected to the tractor for movement 'm a vertical planewhereby the wheelV moves with the tractor as the tractor crowds forward,backtracks, and swings in a horizontal plane, and moves independently ofthe tractor in a vertical plane, power means for rotating the wheel,powering the `crawler truck and swinging the tractor, ladder and wheelwith respect to the truck, said power means including a single powerplant carried by the tractor, and power transmission means extendingfrom the tractor to the wheel, said power transmission means being amechanical drive comprising a chain drive extending outwardly along theladder to a sprocket carried by one of two meshing gears `in a gearassembly, a third sprocket driven by the gear assembly, and a secondchain drive extending outwardly to and driving the Wheel, said wheelincluding a bull gear rotatable With the wheel, said bull gear beingdriven by a pinion supported by the ladder and driven from the secondchain drive, said pinion being lcarried by a pinion shaft mounted on theladder, said second chain drive terminating at a sprocket secured to asleeve which in turn surrounds the shaft, said sleeve being operativelyconnected to the pinion shaft by a coupling assembly, one-half of thecoupling assembly being carried by the pinion shaft and the other halfbeing operatively connected to the pinion sleeve, said coupling halvesbeing connected by a plurality of shea-r pins, said pins being sodimensioned `as to be the structurally weakest part of the powertransmission system whereby failure of the power transmission system dueto an overload on the Iwheel will 'break the shear pins, said wheelincluding a plurality of buckets mounted about .the periphery thereof,and means -for discharging excavated material at a point remote from thewheel.

2. In a lwheel excavator, -a crawler truck, a tractor mounted forswinging movement in a horizontal plane about the truck as 'a base, `anexcavator wheel, an eX- cavator wheel ladder, said wheel being rotatablymounted on the ladder at its outboard end, said ladder being conriectedto the tractor for swinging movement therewith in la horizontal planeand pivotally connected to the tractor `for movement in Ia verticalplane whereby the wheel moves with the tractor as the tractor crowdsforward, backtracks, and swings in a horizontal plane, and movesindependently of the tractor in a vertical plane, power means forrotating the wheel, powering the crawler truck and swinging the tractor,ladder, and wheel with respect to the truck, said power means includinga single power plant carried hy the tractor, power transmission meansextending from the tractor to the wheel, said wheel in cluding amechanical drive comprising a chain drive extending outwardly along theladder to a sprocket carried by one of two meshing gears in a gearassembly, a third sprocket driven by the gear assembly, and a secondchain drive extending outwardly to and driving the wheel, said gearassembly sprocket being receivable on either one of the two meshinggears whereby the direction of rotation of the second chain drive, andconsequently the Wheel, may be reversed by changing the gear assemblysprocket from one meshing gear to the other, said wbeel including aplurality of buckets mounted about the periphery thereof, and means yfordischarging excavated material at a point remote from the wheel.

3. The wheel excavator of claim `2 further characterized in that thebuckets are bolted to the wheel whereby, upon reversal of the directionof wheel rotation, the buckets can be rotated degrees by removal andreinstallation of the bolts.

References Cited in the file of this patent UNITED STATES PATENTS242,484 Smith June 7, 18811 932,857 Glogner Aug. 3,1, 1909 2,153,719Kuhsel Apr. 11, 1939 2,732,641 Iespersen Jan. 31, 11956 42,926,438 KolbeMar. 1, 1960

